1 files changed, 60 insertions, 0 deletions
diff --git a/dotnet/Mammoth/Couscous/mammoth/internal/util/Iterables.cs b/dotnet/Mammoth/Couscous/mammoth/internal/util/Iterables.cs
new file mode 100644
index 0000000..b1e1477
--- /dev/null
+++ b/dotnet/Mammoth/Couscous/mammoth/internal/util/Iterables.cs
@@ -0,0 +1,60 @@
+using System.Collections.Generic;
+using System.Linq;
+using Mammoth.Couscous.java.lang;
+using Mammoth.Couscous.java.util;
+using Mammoth.Couscous.java.util.function;
+
+namespace Mammoth.Couscous.org.zwobble.mammoth.@internal.util
+{
+	internal static class Iterables
+	{
+		internal static T getFirst<T>(Iterable<T> iterable, T defaultValue) {
+			var iterator = iterable.iterator();
+			if (iterator.hasNext()) {
+				return iterator.next();
+			} else {
+				return defaultValue;
+			}
+		}
+		
+		internal static Optional<T> tryFind<T>(Iterable<T> iterable, Predicate<T> predicate) {
+			var iterator = iterable.iterator();
+			while (iterator.hasNext()) {
+				T value = iterator.next();
+				if (predicate.test(value)) {
+					return new Some<T>(value);
+				}
+			}
+			return new None<T>();
+		}
+		
+		internal static Iterable<T> lazyFilter<T>(Iterable<T> iterable, Predicate<T> predicate) {
+			var enumerable = FromJava.IterableToEnumerable(iterable).Where(predicate.test);
+			return ToJava.EnumerableToIterable(enumerable);
+		}
+		
+		internal static Iterable<U> lazyFilter<T, U>(Iterable<T> iterable, System.Type type) {
+			var enumerable = FromJava.IterableToEnumerable(iterable).OfType<U>();
+			return ToJava.EnumerableToIterable(enumerable);
+		}
+		
+		internal static Iterable<U> lazyMap<T, U>(Iterable<T> iterable, Function<T, U> function) {
+            var enumerable = FromJava.IterableToEnumerable(iterable)
+                .Select(function.apply);
+			return ToJava.EnumerableToIterable(enumerable);
+		}
+		
+		internal static Iterable<U> lazyFlatMap<T, U>(Iterable<T> iterable, Function<T, Iterable<U>> function) {
+            var enumerable = FromJava.IterableToEnumerable(iterable)
+                .SelectMany(element => FromJava.IterableToEnumerable(function.apply(element)));
+			return ToJava.EnumerableToIterable(enumerable);
+		}
+		
+		internal static Iterable<T> lazyConcat<T>(Iterable<T> first, Iterable<T> second) {
+            var enumerable = FromJava.IterableToEnumerable(first)
+				.Concat(FromJava.IterableToEnumerable(second));
+			return ToJava.EnumerableToIterable(enumerable);
+		}
+	}
+}
+